What can be terrorist psychology?

Tweet

This world faces lot of terrorist attack? What do you think why they dont fear from even death also? As it is said that "Man is social animal".Then Why they kill to innocent peoples. What can be their psychology? Are they not human beings? Well Whatever it is. I think they are not human beings, they are not animals,not monsters or evil also.They are terrorist entirely different kind of species. what do you say?